THE BIRDS OF NORTHERN THAILAND 495 



sides of the head and neck dark ashy gray, changing to dark olive- 

 green on the rest of the crown, the nape, and the remaining upperparts 

 (the wings tinged with rufescent) ; the long tail light rufescent olive- 

 green ; the chin, throat, and breast white, slightly washed with buffy ; 

 the remaining imderparts bright yellow, suffused with buff along the 

 flanks; the thighs rufous-buff. 



PRINIA ATROGULARIS ERYTHROPLEURA (Walden) 



Peguan White-browed Hill Prinia 



Suya erythrGplevra Walden, in Blyth, Catalogue of the mammals and birds of 

 Burma, Journ. Asiat. Soc. Bengal, vol. 43, pt. 2, extra no., 1875, p. 116 

 (Toungoo, Burma). 



Suya superciliary superciliaris, de Schauensee, Proc. Acad. Nat. Sci. Phila- 

 delphia, 1929, p. 556 (Doi Suthep) ; 1934, p. 231 (Doi Suthep, Doi Chiang 

 Dao).— Deignan, Journ. Siam Soc. Nat. Hist. Suppl., 1931, p. 150 (Doi 

 Suthep) ; 1936, p. 118 (Doi Suthep).— Riley, U. S. Nat. Mus. Bull. 172, 1938, 

 p. 440 (Doi Langka, Doi Hua Mot). 



The hill prinia occurs from 4,400 to 5,500 feet in stands of lalang, 

 and its numbers vary from one locality to another directly with the 

 extent of such growth at sufficiently high elevations. Thus, while it 

 is very common on Doi Suthep and only slightly less so on Doi Ang 

 Ka, it is wholly unknown from Doi Khun Tan and in the provinces 

 east of the Khun Tan chain has been found only on Phu Kha. 



Along the topmost ridge of Doi Suthep the small bands of this 

 species are a familiar sight, thanks to the curiosity that induces them 

 to come to the edge of a trail or the tops of the grass to scold the 

 passerby. Its habits seem to differ in no important particular from 

 those of its congeners. 



Postjuvenal molt is shown by specimens of April 25 (Doi Langka) 

 and July 14 (Doi Suthep) ; postnuptial molt, by birds of August 12 

 (Doi Hua Mot) and October 26 (Doi Suthep). 



An adult male had the irides olive-gray; the maxilla dark horny 

 brown, fleshy along the edges of the commissure ; the mandible fleshy; 

 the rictus bright yellow ; the feet, toes, and claws fleshy. There seems 

 to be no seasonal change in the color of the bill in this form. 



The adult in winter dress has the entire upperparts olivaceous- 

 brown, suffused with rufescent on the mantle, wings, and tail ; the lores 

 black; a conspicuous superciliary stripe white; the chin, throat, breast, 

 and center of the abdomen buffy white (the feathers of the breast 

 with narrow black lateral edgings, which give an irregularly streaked 

 appearance), changing to rufous-buff along the flanks and on the 

 thighs and under tail coverts. In summer it differs in having the 

 upperparts almost free of rufescent tinge ; the rufous-buff of the under- 

 pays paler ; the tail shorter. 



